document.write( "Question 217322: Find all the angles between 0° to 360° inclusive which satisfy the equation
\n" );
document.write( "i) 2cot^2x + 5 = 7cosecx ii) 2cos^2x + 3sinx = 3 \n" );
document.write( "
Algebra.Com's Answer #163888 by chibisan(131) You can put this solution on YOUR website! i) \n" ); document.write( "cot^2x = cosec^2x -1\r \n" ); document.write( "\n" ); document.write( "2cot^2+5=7cosecx \n" ); document.write( "2(cosec^2x-1)+5 = 7cosecx \n" ); document.write( "2cosec^2x -2 + 5 = 7cosecx \n" ); document.write( "2cosec^2x -7cosecx +3 = 0 \n" ); document.write( "(2cosecx-1)(cosecx - 3)= 0\r \n" ); document.write( "\n" ); document.write( "cosecx = 1/2 \n" ); document.write( "1/sinx = 1/2 \n" ); document.write( "sinx = 2 \n" ); document.write( "(no solution)\r \n" ); document.write( "\n" ); document.write( "cosecx=3 \n" ); document.write( "1/sinx = 3 \n" ); document.write( "sinx =1/3 \n" ); document.write( "x = 19.5° , 180 - 19.5° \n" ); document.write( "x = 19.5 , 160.5° (ans)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "ii) \n" ); document.write( "2cos^2x + 3sinx = 3 \n" ); document.write( "2(1-sin^2x) + 3sinx - 3=0 \n" ); document.write( "-2sin^2x + 3sinx + 1= 0 \n" ); document.write( "0= 2sin^2x - 3sinx + 1 \n" ); document.write( "0= (2sinx- 1)(sinx - 1)\r \n" ); document.write( "\n" ); document.write( "sinx = 1/2 \n" ); document.write( "x = 30° , 180 - 30° \n" ); document.write( "x = 30° , 150°\r \n" ); document.write( "\n" ); document.write( "sinx =1 \n" ); document.write( "x= 90°, 180°-90° \n" ); document.write( "x = 90°\r \n" ); document.write( "\n" ); document.write( "x= 30° , 90° , 150° (ans) \n" ); document.write( " |